svcrpc: fix double-free on shutdown of nfsd after changing pool mode
The pool_to and to_pool fields of the global svc_pool_map are freed on shutdown, but are initialized in nfsd startup only in the SVC_POOL_PERCPU and SVC_POOL_PERNODE cases. They *are* initialized to zero on kernel startup. So as long as you use only SVC_POOL_GLOBAL (the default), this will never be a problem. You're also OK if you only ever use SVC_POOL_PERCPU or SVC_POOL_PERNODE. However, the following sequence events leads to a double-free: 1. set SVC_POOL_PERCPU or SVC_POOL_PERNODE 2. start nfsd: both fields are initialized. 3. shutdown nfsd: both fields are freed. 4. set SVC_POOL_GLOBAL 5. start nfsd: the fields are left untouched. 6. shutdown nfsd: now we try to free them again. Step 4 is actually unnecessary, since (for some bizarre reason), nfsd automatically resets the pool mode to SVC_POOL_GLOBAL on shutdown. Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
parent
b8548894bd
commit
61c8504c42
|
@ -167,6 +167,7 @@ svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
|
|||
|
||||
fail_free:
|
||||
kfree(m->to_pool);
|
||||
m->to_pool = NULL;
|
||||
fail:
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
@ -287,7 +288,9 @@ svc_pool_map_put(void)
|
|||
if (!--m->count) {
|
||||
m->mode = SVC_POOL_DEFAULT;
|
||||
kfree(m->to_pool);
|
||||
m->to_pool = NULL;
|
||||
kfree(m->pool_to);
|
||||
m->pool_to = NULL;
|
||||
m->npools = 0;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue